10-4
So anybody try a wideband O2 on a crossrammed Hemi yet?
- Thread starter 2blader
- Start date
68 HEMI GTS
Well-Known Member
Almost ready to fire mine in the car. Will be tuning the 850’s to start.
no,,u put it in from the bottom and with the right length it protrudes down low enough where u can put a wrench on it without interfering with the carb or intake manifold. 10-32. get several length pairs and u will be able to figure it out easily.
Checked it out, can do. You'll need to remove carb to remove screw in base now. Start hex head screw hex first then put hex wrench in from top until it's at the top. Adjust secondary where you want to start. You may want to remove secondary diaphragm to bring hex to top of base. Don't buy a screw that's to long, 1/2" maybe the longest you can run. Think I use 3/8", can't see a reason to run a longer screw.
I just made one as I have a small hardware store in my home shop.
What CID and camshaft?
68 HEMI GTS
Well-Known Member
What I figured. I have a 472 and with a cam like this it behaves even snottier. Mine is a bit more aggressive I think than yours. I wish it was a tad tamer for the street but that is the way it came. Mine made 730 at the crank at 6800 but was built in 2009….and TY for the info.
Did you dyno it with the crossram or did it have a single dominator? BTW that dart is killer lookin.
Last edited:
For those that do not have vacuum ports on their xrams. What I did.
68 HEMI GTS
Well-Known Member
Cross ram was acting up on the dyno. It had a pretty good vacuum leak. I ran it with an unported Parton single plane and an 1150. That’s the only full pull I made on it due to time. Pretty sure it’s got power left on the table. I think the cross ram is going to rip if I can get it figured out.
Last edited:
Believe it or not they make more with the single plane and Dominator. When I got the car it needed some carb work and Barton is around 3 hours from my house. Sent him the carbs and talked to him on the phone a few times about the car. It was a garage trophy and never really built to be driven…long story. Anyhow having little experience with Hemis or Mopar (came from BBC Chevelles) I figured I would get a head start. Took the car to him after I removes the intake and cleaned everything up. The car had tons of leaks. They installed the intake, carbs and ran it on the hub dyno. He and I went to lunch. He is a great guy. Told me it had another 30+ with the single plane with a Dominator but the xram is just too cool lookin for me to give up on right now. I did think it was a tad light on the numbers making 585 at the wheels. I think either the rear end gear was different as listed or the clutch was slipping. I installed a dual disc after that. Been there running out of time on the dyno as its isn’t cheap. I was hoping for them to tinker more but thems the brakes.
68 HEMI GTS
Well-Known Member
I’ve talked with Ray a few times. Great guy! He’s all over on these intakes though. He told me a ported single plane and ported xram would make the same HP but the xram would make more midrange torque. He also told me his xram and the mp xram would make the same power. A friend of mine had his hemi dyno’d at rays with the mp xram and ray said his mag unit would be 60 better.?? I was taking to Mike Schaffer, he said on his car the Barton ram was about 40hp better than the MP. Then I talked to another guy who’s ran both the single and the mag xram combo’s on a 1000HP hemi. His dyno sheets were really close. Granted though he only had a 1050 on it… seems kind of small, mine picked up with an 1150 and I think it would have handled a 1250. I’ll try to find his sheets. In the case of the single I ran, it was the older style and didn’t have any porting. Is was quite a bit smaller than the ports on the heads. My xram has a really good port match so I’m expecting a bit more power but who knows. Running it for the looks as well, the single would be a hell of a lot easier.. lol
Did an edit to post #158 secondary throttle plate adjustment set screw is I believe 8-32 nc. Had two picked out of bin at hardware 8-32 screws in 10-24 bin.
I was able start hex end in from bottom and back out from bottom to top. Just held secondary plates open.
I was able start hex end in from bottom and back out from bottom to top. Just held secondary plates open.
Last edited:
Yea, always wanted to go efi but thats a **** show too. I think in the end I may have to change the cam shaft to something a tad easier to deal with on the street but will stick with it for now. Thats a lot of cam shaft for a small cube Hemi on my end. ….and yea the 1250 would make sense.
Received 8-32 x x1" Ground head thinner so secondary will close. Had to cut small moon in base plate for hex to bottom out. See black marker. Last picture secondaries closed. Note space. Have thin 1/4"wrench to fit on hex to adjust if engine is running. Thinned out hex head 1st pic on right. Edit: Should have bought 8-32 x 3/8" 1/2" to long. Cut the 1/2" down ordered 3/8" to have them.
Last edited:
Whelp got back to it finally today. That tip works well. Got the idle squared away while the car was warm and let it run then it started to falter and it wouldn’t keep the same idle rpm unless I added more idle screw to it. Then was sitting in the car while running with no air cleaners on it and noticed a ton of fuel vapor pouring out the carb vent tubes on the primary side. Car has been running a while now. At this point everything is heat sinked hot from running...not just the coolant. I started thinking if maybe the fuel lines etc. are not run well and are getting to hot for the fuel? Could that affect the idle quality as the car gets to true operating temperature? NO, I-didn’t build it. The one fuel line (stainless braided) was 150 degrees and the other 135 at the top of the intake manifold. The idle also seemed to react less to inputs than before. Either it would stumble or maybe go up a tad. Maybe a fuel pump issue….has this weird lookin cylindrical mechanical thing. NOT the normal looking one.
As I look it seems the fuels lines maybe too close to the heat.
my secondary idle screws with custom wrench.
with the QFT metering blocks and secondary jet plates with smaller idle bleeds its real close.
squared the primarys to transition slots and only adj idle with the secondarys, idle is at 1500 and drops to 1000-1100 in gear. does not load up. all 4 mixture screws r responsive with these qft blocks.
holley 770 cfm 4235-36.still playing with diaphram springs. purples r now in and going to long yellow springs. i think it needs more secondary jet plate. lean pop under hard acceleration.
with the QFT metering blocks and secondary jet plates with smaller idle bleeds its real close.
squared the primarys to transition slots and only adj idle with the secondarys, idle is at 1500 and drops to 1000-1100 in gear. does not load up. all 4 mixture screws r responsive with these qft blocks.
holley 770 cfm 4235-36.still playing with diaphram springs. purples r now in and going to long yellow springs. i think it needs more secondary jet plate. lean pop under hard acceleration.
Last edited:
Mine is a stick car so I wanna get the idle down from 1500. I can get it around 1100 but like I said above when everything got warm it stumbled. I am asking is 150 degrees is too hot for a a fuel line to get at the carb inlet? Cannot even touch it for long. That means the fuel is extremely warm/hot too which causes idle issue from vapor lock. It also surges a little here and there. Coming from BBC Chevelles with a single carb this is well new to say the least.
Similar threads
